A novel electrochemiluminescence biosensor: Inorganic-organic nanocomposite and ZnCo2O4 as the efficient emitter and accelerator

The detection of specific DNA sequences provides a powerful tool for early diagnosis and prevention of disease. Herein, an enzyme-free electrochemiluminescence (ECL) DNA biosensor was developed by coupling inorganic-organic nanocomposite as the luminophore and ZnCo 2 O 4 as the efficient accelerator. ZnCo 2 O 4 nanoparticles (ZCO NPs), derived from Co and Zn based bimetallic zeolite imidazole framework, was used as the ECL substrate due to their large surface area and excellent catalytic effect. AgInS 2 -ZnS quantum dots (ZAIS) were covalently linked with meso -tetra(4-carboxyphenyl)-porphine (TCPP) to form ZAIS/TCPP inorganic-organic nanocomposites, which were used for the first time as the cathodic ECL luminophore with the coreactant of K 2 S 2 O 8 . Detection of target DNA (tDNA) about chronic myeloid leukemia (CML) was achieved based on dual-signal amplification via cascade toehold-mediated strand displacement reaction (TMSDR). On the basis of experimental results, a limit of detection (LOD) of 200 aM was achieved in the range of 0.5 fM to 1 nM, which showed the excellent performance of this biosensor. This work not only indicates that inorganic-organic nanocomposites as the ECL luminophore is a feasible strategy for efficient emission, but also expands the application of nanomaterials derived from metal organic frameworks.